In a bold move to end offshore tax evasion, around 100 countries have recently embarked on automatic exchange of information about financial income and assets. Drawing on information reports about more than 1 million offshore accounts owned by South Africans, we find that the effect on tax compliance in South Africa is modest: while self-reported foreign financial income increased after the onset of information exchange, it remains below 50% of bank-reported income. Our analysis of comprehensive audit data suggests that the weak compliance effect reflects low utilization of bank-reported information by the tax authorities. In stark contrast to standard theories of tax enforcement with third-party reporting, taxpayers under-reporting foreign financial income face no higher audit probabilities and only slightly higher income adjustments in audits. The results highlight the shortcomings of third-party reporting in contexts where third-party information is imperfect and administrative resources limited.